The overall aims of this proposal are to understand the basic mechanism of cell mediated immunity in man. It is hoped that in some instances we will be able to determine the cause of defects in patients who have diseases associated with depressed cell mediated immunity or hypersensitivity. A better insight into the basic mechanism of cellular immunity may lead to improved forms of therapy for such patients. Since cellular immunity plays a vital role in other biologic phenomena such as transplantation and tumor immunity, this information should be of use in these areas as well. The specific areas of investigation include: 1) An investigation of the lymphocyte mediator, leukocyte inhibitory factor or LIF, with regard to its potential activity as an enzyme, its effect on polymorphonuclear (PMN) leukocyte function and the possibility of setting up a biochemical assay for this mediator. 2) Further studies with MIF (migration inhibitory factor): to investigate the role of histamine receptor bearing lymphocytes in regulating such lymphocyte functions as MIF production and proliferation. Development of an antibody to human MIF which can be ultimately used to study how this lymphocyte mediator is involved in cellular immune reactions. 3) Clinical studies in patients with anergy with regard to lymphocyte and monocyte function and the role of "suppressor" factors in affecting their responses. Evaluate the significance of a blocking factor in the serum of normal multiparous patients and establish its presence or absence in patients who chronically abort. To further characterize this blocking factor and determine its specificity.